Final answer:
The amount of money originally invested in the function F(x) is represented by the term 1000, which is the initial investment or principal.
Step-by-step explanation:
The term that represents the amount of money originally invested in the function F(x) = 1000(1 + 0.05)x is 1000. This number is the principal or the initial investment upon which the interest is calculated. In the given function, 0.05 represents the interest rate, and x represents the number of periods the interest is applied. Hence, the correct answer is option 1).